I currently own 4 valentine units and have them hardwired in all the cars. I have been a long time V1 owner and the best mode for me is in L mode.
Best radar on the market and has saved me on more than 1 occassion. Great investment. Spend the extra bucks and get it hardwired. It shuts of when the x5 is turned off. If you plug it into the ciagarette lighter, it remains on even after the x5 key is removed.

L mode works best for me in the tristate area. I guess it kind of depends on where you live. I would keep in A mode if you live in montana or wyoming.